This application claims the priority of German application 196 39 565.8-42 filed in Germany on Sep. 26, 1996, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a motor vehicle having a vehicle body support structure which has a passenger compartment, and having a deformable front zone arranged in front of the passenger compartment and effective in the longitudinal direction of the vehicle and a deformable rear zone arranged behind the passenger compartment and effective in the longitudinal direction of the vehicle.
Motor vehicles of this type are generally known in the form of passenger cars. In the event of a frontal impact of the passenger car or in the event of a rear impact onto the passenger car, the deformable front zone and the deformable rear zone have the purpose of reducing impact energy to such an extent that the passenger compartment itself is not deformed. In comparison to the deformable zones, the passenger compartment has a much stiffer design and has an essentially rigid behavior. Particularly in the event of very serious frontal impact loads, the driver-side and/or the front passenger-side front area of the passenger compartment may also deform which may considerably reduce the survival space of the front-side vehicle occupants.
From German Patent Document DE 42 20 438 A1, a compact car is known which has a flexible center part which, according to the requirement, can be retracted or extended. In the extended condition, the center part provides room for an additional seat bench or for additional storage space.
It is an object of the invention to provide a motor vehicle of the initially mentioned type which, particularly in the event of serious impact accidents, provides the vehicle occupants with an increased survival space.
This object is achieved in that at least one deformable center zone, which is integrated into the vehicle support structure and is also effective in the longitudinal direction of the vehicle, is assigned to the passenger compartment. The solution according to the invention therefore advantageously provides an energy reduction within the passenger compartment itself. As a result, a corresponding impact load must not be absorbed exclusively by the deformable front zone or by the deformable rear zone so that, particularly in the event of serious frontal impact loads, intrusions of the front area of the passenger compartment and therefore a reduction of the survival space of the front-side vehicle occupants can be avoided. Naturally, the at least one deformable center zone is arranged such within the passenger compartment that also the survival space for vehicle occupants in a rear area is not significantly reduced because of this deformable zone. On the one hand, the solution according to the invention has important advantages in the event of very serious impact loads in that intrusions in the front area of the vehicle occupant compartment are avoided by an energy absorption in the area of the at least one deformable center zone within the vehicle occupant compartment itself. On the other hand, the solution according to the invention is also suitable for improving the compatibility between very large and very small passenger cars since, when the solution according to the invention is used, the very large passenger cars are provided with an enlarged energy absorption path which reduces the impact accelerations for a small passenger car in the event of a collision with this very large passenger car. The solution according to the invention therefore achieves a considerable improvement of the passive safety of a motor vehicle.
As a further development of the invention, the at least one deformable center zone is provided in the transition area between seat positions of the passenger compartment arranged behind one another in the longitudinal direction of the vehicle at least at the level of the floor structure of the passenger compartment. This further development is based on the fact that a space is available in the transition area between seat positions arranged behind one another which is not required for the survival space of the respective vehicle occupants on the rearward seat positions so that the providing of a deformable center zone in this area has no disadvantageous effect on the rear vehicle passengers. In the case of a four-seat passenger car, the deformable center zone is situated in the transition area between the front-side and the rear-side seat positions. In the case of a large-capacity sedan which has more than two rows of seats arranged behind one another, two or more deformable center zones may also in each case be provided in the transitions areas between the seat positions which adjoin one another in the longitudinal direction of the vehicle.
In a further development of the invention, the deformation resistance of the at least one deformable center zone is coordinated such with the deformable front and rear zones that the deformable center zone does not become effective before at least the deformable front zone or the deformable rear zone is used at least partially for the absorption of energy. This ensures that the deformable center zone is used exclusively in the event of serious impact loads so that, in the event of low or medium impact loads, the passenger compartment remains stiff and repairs will be required only with respect to the deformable front zone or the deformable rear zone.
In a further development of the invention, the deformable center zone has weakenings at defined points of the floor structure. The weakenings can be achieved either by means of a correspondingly flexible design of the support parts of the floor structure at the defined points or by an additional stiffening of the remaining relevant areas of the floor structure, whereby the unreinforced areas automatically form weakenings in the sense of this further development.
As a further development of the invention, several deformation corrugations are provided as weakenings which are arranged behind one another in the longitudinal direction of the vehicle and which are integrated in the floor structure of the passenger compartment. The floor structure includes the lateral chassis members as well as the vehicle floor and optionally a transmission tunnel provided for, a propeller shaft. Deformation corrugations can be provided without any major cost expenditures within the floor structure made of pressed sheet metal parts. Because of the fact that deformation corrugations are provided only in the area of the floor structure and not in the area of the roof structure, the passenger compartment is pushed together only in the area of the floor structure at whose level the main forces are introduced and buckles in the upward direction in the area of the roof structure. As a result, the portion of the passenger compartment which is in the rear in the direction of the impact load will tip by a certain amount. This has advantages in the event of a frontal impact because a submarining effect for the rear passengers is reduced because of the increased tilting of the seat surfaces of the rear seats as the result of the tipping of the rear-side portion of the passenger compartment.
In a further development of the invention, the deformation corrugations of the floor structure are arranged in the transition area between lateral B-columns and a rear seat cross member. This is a particularly favorable positioning of the deformation corrugations because, even in the event of a deformation in this area, the rear occupants still have sufficient survival space.
In a further development of the invention, the floor structure has deformation elements which are positioned in the area of the front ends of lateral chassis members facing the front wheels. This further development is advantageous particularly in the event of an offset frontal impact because the correspondingly loaded front wheel will act early upon the deformation element preferably developed as an impact absorbing element and will thus concentrate the impact forces on the assigned lateral chassis member. Since the corresponding weakenings for the deformable center zone are also provided in this lateral chassis member, the deforming of this deformable zone is promoted by this further development.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.